Resilient surface coverings, and in particular resilient floor coverings, are well known in the art. The floor coverings which are in wide use today are primarily of vinyl construction and, although they can be constructed to have varying degrees of flexibility, they are "resilient" when compared to conventional natural materials, such as ceramic tile. A variety of such products are commercially available and these products have proven to exhibit good wear resistance; however, such coverings are not without certain deficiencies. For example, although vinyl flooring products are durable and stain resistant, they nevertheless tend to lose their glossy appearance through wear. A high-gloss appearance for a floor covering is often desired. Accordingly, the manufacturers of such materials have long sought to find improved floor coverings which exhibit good gloss retention.
One method of providing improved gloss retention is through the application of polyurethane or other wear layers to vinyl flooring structures. Such materials are durable and relatively scratch resistant, and they tend to retain their high-gloss appearance over a longer period of time than do vinyl-surfaced flooring structures. Nevertheless, these wear layers, and in particular polyurethane wear layers, also have certain drawbacks. For example, they are more susceptible to staining; thus, when exposed to common household stains as ballpoint pen, lipstick, mustard, shoe polish and the like, polyurethane coatings tend to be more easily stained than vinyl coatings.
In recent years, the coatings industry has expended considerable effort to develop new and different types of urea or melamine-formaldehyde resins, often referred to as aminoplasts. Such materials may be urea-based or they may be melamines (triaminotriazines) which have been N-alkylated with formaldehyde to provide a methylolated or partially methylolated melamine. The methylol groups are then etherified or partially etherified to provide a crosslinking agent. Such materials have found wide use in coatings for automobiles, appliances and other fairly rigid types of surfaces, and they have also been used in coatings for certain flexible substrates including paper, paperboard, metal foils, cellophanes and the like. However, such materials have never been successfully applied to flooring structures, and in particular to vinyl flooring structures.
Accordingly, one objective of the present invention is to provide resilient surface coverings with protective surfaces which will deform in response to the application of physical stresses on the surface coverings, yet will provide improved scratch and stain resistance.
Another objective of the present invention is to provide flooring structures comprising composite wear surfaces whereby the wear layer material is provided with an improved scratch and stain-resistant character.
These and other advantages of the present invention will become apparent from the detailed description of preferred embodiments which follows.